Many proteins involved in the clotting cascade, including, e.g., Factor VII, Factor VIII, Factor IX, Factor X, and Factor XIII, are proving to be useful therapeutic agents to treat a variety of pathological conditions. Generally, the blood components which participate in what has been referred to as the coagulation “cascade” are proenzymes or zymogens, enzymatically inactive proteins which are converted to proteolytic enzymes by the action of an activator, itself an activated clotting factor. Coagulation factors that have undergone such a conversion and generally referred to as “active factors,” and are designated by the addition of a lower case “a” suffix (e.g., activated factor VII (FVIIa)).
Because of the many disadvantages of using human plasma as a source of pharmaceutical products, it is preferred to produce these proteins in recombinant systems. The clotting proteins, however, are subject to a variety of co- and post-translational modifications, including, e.g., asparagine-linked (N-linked) glycosylation; O-linked glycosylation; and γ-carboxylation of glu residues. For this reason, it is preferable to produce them in mammalian cells, which are able to modify the recombinant proteins appropriately.
In the production of clotting proteins from cultures of microorganisms or cell lines, the final production step is the recovery and optionally the concentration of the product of interest. Culture media in which the cells have been grown and which contain secreted proteins, and, in particular, cell lysates containing intracellular proteins of interest also contain, to a greater or lesser extent, other proteins produced by the cells, apart from other contaminants, such as media components, nucleic acids and the like. In order to obtain a purified protein product, it is therefore necessary to separate the protein of interest from other proteins and polypeptides and other impurities in the crude material containing the protein of interest.
U.S. Pat. No. 5,700,914 relates to a method for FVII purification, wherein zinc is present in at least in one of the purification steps.
During the traditional steps of cultivation, purification and in the traditional formulations the activated clotting proteins have a tendency to autodegrade due to the proteolytic function of the proteins. Thus, there is a need in the art for improved methods for cultivation, purification and formulation of activated clotting proteins to reduce the autodegradation during the production of clotting proteins, particularly recombinant human Factor VII or Factor VII-related polypeptides.